This invention relates to a connector assembly for electrically coupling a shielded cable to a ground plane.
In a typical interconnection system, circuit packs with connectors on one edge are electrically coupled to pins emerging from a backplane. Cables are also electrically coupled to pins emerging from the opposite surface of the backplane. (See, e.g., AT&T Technical Journal, Vol. 66, pp. 81-95 (July/August 1987).) In the case of cables with electromagnetic interference (EMI) shielding, the cable shield is typically coupled to designated pins in the backplane which are, in turn, coupled to a ground plane on the backplane surface. While such a ground connection is adequate for most applications, in the case of high frequency signals, problems can arise if the transfer impedance of the shield connection is not sufficiently low. Shield connections that do not have low enough transfer impedance can result in unacceptable high levels of electromagnetic emissions from the cable or unacceptable susceptibility to external sources of electromagnetic radiation. In addition to a ground path for the shield which is a part of the cable, cable connectors may also require an ability to be stacked end-to-end and some sort of keying function which prevents insertion of the plug in the wrong position.
Metal shrouds have been proposed for ground connection of a variety of connectors to circuit boards (see, e.g., U.S. Pat. No. 4,903,402 issued to Norton et al., U.S. Pat. No. 5,040,999 issued to Collier, and U.S. Pat. No. 5,288,247 issued to Kaufman).
It has also been suggested in providing connection of daughter boards to backplanes to include a ground or power contact in the side wall of a shroud mounted to the backplane (see U.S. Pat. No. 4,869,677 issued to Johnson et al.).